There is a way to use differential braking while on the ground, which basically means that you are steering the airplane by braking one wheel and not the other. So, if you want to go left, use the left brake only and vice versa for the right. Unfortunately, I haven't installed FS
2004 on my new laptop yet so I can't look up the controls, so I'll leave that to you guys! Hope that helps!
BTW, its a lot easier to use differential braking than it is to keep locking and unlocking the tailwheel.